Keyed latch valve for fuel filter

ABSTRACT

A fuel filter includes a housing and a pipe in the housing. The pipe includes a central flow passage, an opening along the length of the pipe into the passage, and an exterior groove. A latch device with discrete fingers closely surrounds the pipe and is engageable with the groove to prevent the latch device from moving axially along the pipe. The latch device has an annular sleeve, radially-outwardly spaced from the fingers. A valve device surrounds the pipe and has a sleeve normally covering the pipe opening in the pipe. A filter element has an end cap with thin, flat keys. The keys project through the slots in the valve device and engage the sleeve of the latch device to unlock the latch device from the pipe, and also engage and move the valve device to uncover the opening in the pipe, when the filter element is inserted into the housing.

This application is a national stage application of International PatentApplication serial No. PCT/US00/31329 filed on Nov. 15, 2000, and claimsthe benefit of U.S. Non-Provisional Patent Application Ser. No.09/452,857 filed on Dec. 3, 1999, now U.S. Pat. No. 6,495,042, andclaims the benefit of U.S. Provisional Patent Application No. 60/168,941filed on Dec. 3, 1999.

This invention relates to fluid filters, and more particularly to fuelfilters for vehicles.

Many types of fuel filters (also referred to as “separators”) are knownin the prior art. A popular type of fuel filter has a housing thatencloses a replaceable ring-shaped filter element. The filter elementensures that impurities are removed from fuel before it is delivered tosystem components such as fuel injection pumps and fuel injectors.Mating portions of the housing form an interior enclosure for theelement, and the housing portions may be separated for replacement of aspent filter element. Periodic replacement of the filter element isrequired so that the filter element will not become so loaded withimpurities that fuel flow is restricted. Cost and ease of manufacturehave been important considerations with such elements. However, problemsmay arise when such filter elements are replaced.

One problem is that filter elements with different sizes and/orfiltration capabilities often have identical mounting configurations andcan fit on the same filter head. However, use of the wrong filter cancause poor engine performance and allow undesirable amounts ofcontaminants to pass through the fuel system.

Another problem is that individuals may remove a spent filter elementand simply re-attach the housing portions without a fresh element. Whilethe engine may operate (at least for a short period of time), this canbe detrimental to the engine.

A still further problem is that disturbance of the spent element duringreplacement may cause collected impurities to fall off the element. Insome designs, these impurities may pass into the outlet of the filterhousing and reach the components downstream in the fuel system.

To reduce and at least partially eliminate these problems, the filterassembly shown in Patent Specification U.S. Pat. No. 4,836,923, owned bythe Assignee of the present application, was developed. This filterincludes a unique replaceable filter element that is attached to aremovable cover. The housing has an internal standpipe with an openingat the top end. When the element is removed from the housing, the fuellevel in the housing falls below the opening in the standpipe. As aresult, the impurity-laden fuel left in the housing is less likely toreach the outlet. Likewise, when a new element is installed in thehousing, only fuel that has been purified by passing through the mediaof the element is enabled to reach the opening and pass out of thehousing.

While this filter design has many advantages, if the filter element isnot removed carefully, impurity-laden fuel in the housing or from theouter surface of the element may fall into the opening in the standpipe.If this happens, some impurities may still reach the downstreamcomponents of the fuel system.

In addition, the cover is discarded with each spent element. This isundesirable from a conservation and solid waste standpoint. It isgenerally desirable to minimize the amount of material discarded,particularly if a discarded element must be treated as hazardous waste.The cover also represents a portion of the cost of the replacementelement. As a result this design adds cost to the replacement element.Further, the element may be separated from the cover, and the coverre-attached to the housing without a fresh element also being installed.As such, it still does not fully address the problems associated withoperating an engine without a filter element installed.

A further improved filter is shown in Patent Specification U.S. Pat. No.5,770,065, also owned by the assignee of the present application. Inthis filter, the filter element is received around a standpipe extendingcentrally in the housing. A spring-biased valve element internal to thestandpipe is normally closed, and can be engaged and moved to an openposition by a projection on the element when the element is properlyinstalled in the housing. This filter provides the advantages of the'923 patent, as well as prevents impurity-laden fuel from passingthrough the standpipe when the element is changed. The assembly alsoprevents operation of the engine without an appropriate element inplace.

The filter shown in the '065 patent has received wide-spread acceptancein the marketplace. Nevertheless, it is believed that there exists aneed for a still further filter which has the advantages of the '065patent, but where the valve structure is located exterior to thestandpipe. Such a valve structure can be easier to manufacture andassemble, thereby reducing the cost of the assembly. It is also believedthere is a demand for a filter where the opening into the standpipe islocated toward the lower end of the filter. This can prevent or at leastreduce the chance of pulling air into the system, as the opening is keptbelow the level of the fuel.

As such, it is believed that there exists a need for a further improvedfuel filler which overcomes at least some of the above-describeddrawbacks.

According to one aspect of the present invention there is provided afilter subassembly comprising a filter element including a ring offilter media circumscribing a central axis. The ring has a first end anda second end. First and second end caps are fixed to the first andsecond ends, respectively, of the filter media. The second end cap hasan annular end cap portion sealingly bonded to the second end of thefilter media and a valve-actuating portion. The valve-actuating portionincludes an axially extending cylindrical portion connected to theannular end cap portion and circumscribing the inner diameter of theannular end cap portion. An annular base is connected to the cylindricalportion and extends radially inward from the cylindrical portion todefine a first central opening which can receive a pipe. At least onekey is provided with the valve actuating portion having an engagingportion radially inward spaced from the cylindrical portion and axiallyspaced away from said annular base.

A new and unique fuel filter is thereby provided that prevents animproper filter element from being used in the filter and preventsoperation of the filter without a filter element in place. The filter issimple and low-cost to manufacture and assemble, and prevents air fromentering the system.

According to the present invention, a pipe extends centrally within thehousing, and a valve structure is provided externally to the pipe. Inone embodiment, the pipe is a standpipe fluidly connected to the outletport; while in another embodiment the pipe is an inlet pipe to a fuelpump in the housing. In either embodiment, the pipe includes a centralfluid passage and an opening into the passage toward the lower end ofthe pipe. A radially-outward facing groove or channel is providedcircumferentially around the pipe, near the opening.

The valve structure for the filter includes a valve device and a latchdevice, with the valve device including a sleeve closely surrounding thepipe. The valve device further includes an annular, radially-outwardprojecting base surrounding the sleeve. A series of radially-outwardprojecting tabs are spaced around the periphery of the base. The valvedevice can be easily manufactured unitarily in one piece frominexpensive material, such as plastic.

The latch device for the valve structure includes a series of deformablefingers in an annular array closely surrounding the pipe. The distalends of the fingers are normally aligned with and engage the groove inthe pipe to prevent the latch device from moving axially along the pipe.The latch device, in the locked position, supports the valve device in aposition such that the valve sleeve blocks flow through the opening inthe pipe. The latch device further includes an annular sleeve radiallyoutwardly-spaced from the fingers. One end of the sleeve, located awayfrom the valve device, is connected to the fingers, while the other endof the sleeve, located adjacent the valve device, defines an annularengagement surface. The latch device likewise can be easily manufacturedin one piece from inexpensive material, such as plastic.

According to the first embodiment, the housing is designed for a“top-loaded” element, and includes a removable lid. In this embodiment,the latch device is located between the valve device and the lower endof the housing, with the annular engagement surface of the latch devicefacing upwardly in the housing and against the base of the valve device.

In the second embodiment, the housing is designed for a “bottom loaded”element, and the latch device is located between the valve device andthe pump, with the annular engagement surface of the latch device facingdownwardly in the housing, and against the base of the valve device.

In either embodiment, a compression spring surrounds the pipe and urgesthe latch device toward the valve device.

The filter element for the fuel filter includes a ring of filter mediacircumscribing a central axis and having upper and lower end caps. Eachend cap has an annular portion bonded to the filter media. The lower endcap has an axially-extending cylindrical portion connected to andbounding the inner diameter of the annular end cap portion, and anannular base projecting radially-inward from the cylindrical portion.The annular base closely surrounds the sleeve of the valve device in thefirst embodiment, and the inlet pipe in the second embodiment.

A key device is located internally of the cylindrical portion of thelower end cap. The key device includes an annular base dimensioned tofit within the cylindrical portion, and a plurality of thin, flat keysprojecting axially away from the annular base. The keys projectaxially-outward (i.e., downward) from the media ring in the firstembodiment (the “top-loaded design”), and axially-inward (i.e., upward)into the media ring in the second embodiment (the “bottom-loaded”design). The keys preferably include a step defining an axially longerand radially thinner portion, and an axially shorter and radially widerportion. The key device, including the base and keys, is also preferablyformed unitarily, in one piece, from inexpensive material, such asplastic. In the first embodiment, a first O-ring is provided in anaxially-outward facing groove in the base of the key device to sealagainst the annular base of the lower end cap; while a second O-ringseal is provided in a radially-inward facing groove in the base to sealagainst the valve sleeve.

The key device is located between the lower end cap of the filterelement and the valve device when the filter element is installed withinthe housing. In the first embodiment, when the filter element isinserted from the upper end of the housing, the keys of the key deviceare received downwardly between the tabs on the valve device. The longerportions of the keys engage the upward-facing engagement surface on thelatch device and cause the latch device to bend, which in turn causesthe fingers to move radially outward from their locking engagement withthe groove in the standpipe. At the same time, the shorter portions ofthe keys engage the base of the valve device and cause the valve deviceto move downwardly along the standpipe, against the latch device, andout of blocking relation with the opening in the standpipe. When theelement is properly positioned in the housing, the opening to thestandpipe is completely open to allow fuel flow through the fuel filter.

In the second embodiment, when the element is bottom-loaded, the keys ofthe key device are similarly received between the tabs on the valvedevice, with the longer portions of the keys engaging thedownward-facing engagement surface on the latch device. This similarlycauses the latch device to bend, and the fingers to move radiallyoutward from their locking engagement with the groove in the pipe. Theshorter portions of the keys at the same time engage the lower surfaceof the base of the valve device and cause the valve device to moveupwardly along the pipe (against the latch device), uncovering the flowopening in the pipe. When the element is properly positioned in thehousing, the opening to the inlet pipe is completely open to allow flowthrough the filter assembly.

The dimensions, number and location of the keys on the key device andthe tabs on the valve device can be selected to allow only a specificfilter element to be used with a particular housing. An incorrectgeometry number or arrangement of keys and/or tabs will prevent a filterelement from being properly located in the housing. The keys and tabsare relatively easy to fabricate, using simple molding operations.

Once a filter element with a proper selection of keys is installed inthe housing, fluid can be provided into the housing and pass through thefilter media ring to be filtered. When the element is to be replaced,the spring assists in removing the element from the housing, and returnsthe valve device to a position blocking the opening in the pipe. Thisprevents unfiltered fuel and contaminants from passing through the pipeand downstream in the system. The location of the opening in the lowerend of the pipe is below the typical level of fuel in the housing, whichprevents air from passing downstream through the system.

The key device, valve device and latch device are easily assembled overthe standpipe and inlet pipe during assembly of the filter housing.

Thus, as described above, the filter of the present invention providesmany of the benefits of the prior art filters such as preventing animproper element from being installed within the housing, and preventingoperation of the filter without and element in place. In addition, thefilter is simple and low cost to manufacture and assemble, and preventsair from entering the system.

The invention is diagramatically illustrated by way of example in theaccompanying drawings, in which:

FIG. 1 is a cross-sectional elevated perspective view of a firstembodiment of the fuel filter constructed according to the principles ofthe present invention;

FIG. 2 is an enlarged cross-sectional elevated perspective view of aportion of the fuel filter shown in FIG. 1;

FIG. 3 is an exploded view of certain components of the fuel filter ofFIG. 1;

FIG. 4 is a cross-sectional side view of a portion of the fuel filter ofFIG. 1, illustrating the open and closed positions of the valvestructure;

FIG. 5 is an perspective view of the lower end cap of the filter elementfor the filter assembly;

FIG. 6 is a cross-sectional side view of a portion of the filterelement;

FIG. 7 is a bottom view of the lower end cap for the filter element;

FIG. 8 is an elevated perspective view of the valve device for the fuelfilter;

FIG. 9 is an elevated perspective view of the latch device for the fuelfilter;

FIG. 10 is a top view of the latch device;

FIG. 11 is a cross-sectional side view of the latch device;

FIG. 12 is a cross-sectional view of a second embodiment of the fuelfilter;

FIG. 13 is an elevated perspective view of the pump assembly and valvestructure for the fuel filter of FIG. 12;

FIG. 14 is a view similar to FIG. 13, but with an exploded view of thevalve structure;

FIG. 15 is an elevated perspective view of the lower end cap for thefuel filter FIG. 12; and

FIG. 16 is a cross-sectional side view of a portion of the filterelement of the second embodiment.

FIG. 17 is a cross-sectional side view of a portion of the filterelement similar to FIG. 6, but showing a separate key device;

FIG. 18 is an elevated perspective view of the key device for the filterelement of FIG. 17;

FIG. 19 is a cross-sectional side view of a portion of the filterelement similar to FIG. 16, but showing a separate key device; and

FIG. 20 is an elevated perspective view of the key device for the filterelement of FIG. 19.

Referring now to the drawings, and initially to FIGS. 1-4, a firstembodiment of a fuel filter constructed according to the principles ofthe present invention is indicated generally at 20. The fuel filter 20is particularly suited for filtering water and other particulates andcontaminants from fuel (e.g., diesel fuel), but is generally appropriatefor separating any low density fluid from a higher density fluid. Thefilter of the first embodiment includes a housing 22 with a lid 24mounted to one end of the housing, and an annular body 26 with acollection bowl 30 mounted to the other end of the housing. The housing22, lid 24 and annular body 26 define an interior cavity 32 for aremovable filter element 34. Housing 22 can include appropriate mountingflanges or brackets 36 or other means to allow the housing to be mountedto an appropriate location in the fluid system. Housing 22, lid 24,annular body 26 and collection bowl are formed from materialsappropriate for the particular application, as should be known to thoseskilled in the art.

Annular body 26 includes an inlet port 38 and an outlet port 39, whichdirect fuel into and out of the filter. Fuel directed through inlet port38 is directed through passage 41 and into collection bowl 30. Valveball 42 prevents back-flow through the passage 41. The fuel initiallypasses through a funnel member 43, and then against a deflector turbine44, which separates water in the fuel. The water collects in the bottomof the collection bowl and can be periodically removed from the housingthrough drain 46. A water sensor 48 can also be provided in thecollection bowl.

The fuel then flows upwardly around the funnel 43, around the passagesforming ports 38 and 39, and around the exterior of filter element 34.The fuel then flows radially inward through the filter element, and intoan opening 49 in a central cylindrical standpipe 50. Opening 49 islocated toward the lower end of the housing, preferably below thetypical level of fuel in the housing to prevent air passing downstreamin the system. Standpipe 50 is connected at its lower end to the annularbody 26, such that the fuel flows through an interior passage 52 in thestandpipe 50 and out through the outlet port 39. Standpipe 50 can beeasily connected to annular body 26 such as with cooperating threads asat 53. Contaminants and particles collecting on the exterior surface ofthe filter element fall down into the collection bowl 30, from whichthey can be periodically removed through drain 46.

When the element 34 is to be replaced, a clamp 56 fixing the lid 24 tohousing 22 is removed. Standpipe 50 extends centrally through thehousing to the open end and provides an easy attachment device for clamp56 to retain the lid in fluid-tight relation with the housing. In anycase, when the clamp 56 is removed, the lid 24 can then be removed, andthe element 34 accessed, removed from the housing, and replaced with afresh element.

Further discussion of the assembly described above can be found inPatent Specification U.S. Pat. No. 3,931,011, owned by the assignee ofthe present invention. It should be appreciated that the assemblyillustrated in FIGS. 1-4 is only exemplary in nature, and other types offilter housings and associate components could be used with the presentinvention.

In any case, a valve structure, indicated generally at 60, is providedtoward the lower end of the housing. The valve structure 60 surroundsthe central standpipe 50, and controls the flow of fluid through opening49. An outwardly-facing locking groove 62 is provided proximate to, andbelow the opening 49. A second groove below opening 49 carries an O-ring63. Referring now to FIGS. 3 and 8-11, the valve structure 60 includes avalve device, indicated generally at 64, and a latch device, indicatedgenerally at 68. The valve device 64 includes an annular sleeve 70,which is dimensioned to closely fit around the standpipe 50. The upperend surface 71 (FIG. 8) of the sleeve 70 can have a chamfer or taper tofacilitate the movement of the sleeve along the standpipe.

A relatively thin and flat annular base 72 is provided at the lower endof sleeve 70, and projects radially outward therefrom. A series ofradially-projecting supports 74 extend between the base 72 and sleeve 70to provide support for the base. Four such supports are illustrated,however, this can vary depending upon the application, and someapplications may not even require such supports.

A plurality of radially-outward projecting tabs, as at 76, extendoutwardly in a common plane from the annular base of the sleeve. Twelveof such tabs are illustrated, although supports 74 take the place andfunction of the tabs at their particular locations, such thatessentially sixteen of such keys are shown. The tabs 76 are illustratedas being equally-spaced around the periphery of the base, and define aseries of slots, as at 78. Tabs 76 and slots 78 have essentiallyrectangular configurations, however the geometry, as well as the numberand location of the tabs and slots, can vary depending upon theparticular application, as will be described below. Preferably, thevalve device, including the sleeve 70, annular base 72, and tabs 76, isformed unitarily in one piece from inexpensive material (e.g., plastic).

The latch device 68 includes a plurality of fingers, as at 80, in anevenly-spaced, annular arrangement, surrounding the standpipe 50.Fingers 80 each have radially-inward projecting distal ends as at 82,which bound a cylindrical projection (see e.g., FIG. 10) slightlysmaller than the standpipe, such that the fingers are each forcedslightly outwardly when the latch device is received around thestandpipe (see e.g., the right side of FIG. 4). The fingers 80 areconnected at their lower ends to the lower end of an annular sleeve 84,and extend radially-inward from the sleeve, then axially-upward, andfinally radially inward at the distal ends 82. The geometry of thefingers 80 makes them somewhat resiliently deflectable in the radialdirection, although they have good axial rigidity. The number, dimensionand location of fingers 80 can also vary depending upon the particularapplication, as will be described below, although it is preferred thatat least three equally-spaced fingers are provided. Eight equally-spacedfingers, as illustrated, is even more preferred.

Sleeve 84 is radially-outwardly spaced from the fingers, and extendsupwardly from the connection with the fingers to an upper annularengagement surface 86. A spring stop is defined by an annular surface 87at the lower end of the sleeve 84. The latch device, including fingers80 and sleeve 84, is also preferably formed unitarily in one piece frominexpensive material (e.g., plastic).

As illustrated in FIGS. 3 and 4, the latch device 68 is located betweenthe valve device 64 and the annular body 26 at the lower end of thefilter housing. The support for the base. Four such supports areillustrated, however, this can vary depending upon the application, andsome applications may not even require such supports.

A plurality of radially-outward projecting tabs, as at 76, extendoutwardly in a common plane from the annular base of the sleeve. Twelveof such tabs are illustrated, although supports 74 take the place andfunction of the tabs at their particular locations, such thatessentially sixteen of such keys are shown. The tabs 76 are illustratedas being equally-spaced around the periphery of the base, and define aseries of slots, as at 78. Tabs 76 and slots 78 have essentiallyrectangular configurations, however the geometry, as well as the numberand location of the tabs and slots, can vary depending upon theparticular application, as will be described below. Preferably, thevalve device, including the sleeve 70, annular base 72, and tabs 76, isformed unitarily in one piece from inexpensive material (e.g., plastic).

The latch device 68 includes a plurality of fingers, as at 80, in anevenly-spaced, annular arrangement, surrounding the standpipe 50.Fingers 80 each have radially-inward projecting distal ends as at 82,which bound a cylindrical projection (see e.g., FIG. 10) slightlysmaller than the standpipe, such that the fingers are each forcedslightly outwardly when the latch device is received around thestandpipe (see e.g., the right side of FIG. 4). The fingers 80 areconnected at their lower ends to the lower end of an annular sleeve 84,and extend radially-inward from the sleeve, then axially-upward, andfinally radially inward at the distal ends 82. The geometry of thefingers 80 makes them somewhat resiliently deflectable in the radialdirection, although they have good appropriate bonding compound.

Upper end cap 94 has an annular configuration, with a central opening 98(FIG. 3) dimensioned to closely receive the standpipe 50. Upper end cap94 is preferably formed unitarily from an appropriate material, such asan inexpensive plastic.

Lower end cap 96 likewise has an annular configuration, with an annularportion 100 fixed to the lower end of the media and defining a centralopening 101. The lower end cap 96 also has a valve-actuating portion,indicated generally at 102. The valve-actuating portion 102 includes acylindrical portion 104 bounding the central opening 101 and extendingaxially inward into the central cavity 93 to a distal inner end. A flatannular base 108 extends radially inward from the distal inner end ofthe cylindrical portion, and defines a central opening 110. Centralopening 110 in base 108 is co-axial with, but radially smaller than,central opening 101 in annular portion 100. Central opening 110 has adimension so that it is closely received about sleeve 70 of valve device64 (see FIG. 4). A flexible tip 112 (FIGS. 4, 6) can be provided aroundopening 110 to provide a fluid-tight seal with the sleeve.

A plurality of keys, as at 116, are provided internally of thevalve-actuating portion 102. Keys 116 are illustrated as thin and flatstrips, with opposing planar side surfaces facing essentiallyperpendicular to the central axis of the element. The keys are alsoillustrated as being equally-spaced in a spoke-like arrangement aroundthe interior of the valve-actuating portion. Each key has one edgeattached directly to the cylindrical portion 104 and another edgeattached directly to the annular base 108, although the keys could beattached to just one of these elements. One free edge of each keyextends outward, away from the annular base 108, while another free edgeextends radially inward from the cylindrical portion toward the centralaxis. The free also prevents the valve device 64 from moving, at leastaxially downward, and thereby keeps the opening 49 fluidly closed by thesleeve 70. The axially upper and radially inner edge of the distal ends82 of the fingers can have a slight chamfer or curve (see FIG. 9) tofacilitate the finger moving into the groove 62.

Referring now to FIGS. 3-7, the filter element 34 includes a ring shapedmedia 92 circumscribing a central axis “A”, and having a central cavity93. The element is bounded at one end by a first or upper end cap 94 andat the other end by a second or lower end cap 96. Ring-shaped media 92can be any media appropriate for the particular application, includingcotton, paper, cellulose, glass fiber, etc., and can be in anyparticular structure that is appropriate, such as single layer,multi-layer, pleated, non-pleated, etc. The end caps 93 and 94 have agenerally round, flat shape and are fixed in a fluid-tight manner to theends of the media such as by an adhesive or other appropriate bondingcompound.

Upper end cap 94 has an annular configuration, with a central opening 98(FIG. 3) dimensioned to closely receive the standpipe 50. Upper end cap94 is preferably formed unitarily from an appropriate material, such asan inexpensive plastic.

Lower end cap 96 likewise has an annular configuration, with an annularportion 100 fixed to the lower end of the media and defining a centralopening 101. The lower end cap 96 also has a valve-actuating portion,indicated generally at 102. The valve-actuating portion 102 includes acylindrical portion 104 bounding the central opening 101 and extendingaxially inward into the central cavity 93 to a distal inner end. A flatannular base 108 extends radially inward from the distal inner end ofthe cylindrical portion, and defines a central the underlying valvedevice. The supports 74 around the base 72 of the valve device assist inorienting the keys with the slots. As the element is inserted into thehousing, the lower free edges of the keys press down against the sleeve84 of the latch device, and cause the latch device to bend outwardly andpull the fingers 80 radially outward from the standpipe. As the fingersare pulled outward, the distal ends 82 of the fingers are pulled outwardfrom groove 62, thus releasing the latch device and allowing the latchdevice to slide axially downward along the standpipe. Again, it ispossible that only a single key extending through the slots in the latchdevice may suffice to unlock the latch device, although that this naycause cocking of the element and/or the latch device, and so at leastthree equally-spaced keys are preferred.

In any case, simultaneously with the fingers being released by theengagement of the keys against the sleeve, the radially wider andaxially shorter portions 119 of the keys engage the upper surface of theannular base 72 of the valve device and push the valve device axiallydownward along the standpipe. The keys are dimensioned to push the valvedevice downward sufficient to fully uncover opening 49 (see theright-hand side of FIG. 4). After the element is installed, fluid canpass through opening 49 in the standpipe, and thus pass to outlet port39. Since the opening 49 is located toward the lower end of the housing,typically below the level of fuel in the housing, this reduces thechance of pulling air in the system when the opening 49 is uncovered.

It should be appreciated that only one or two of the key(s) 116 may havea radially wider and axially shorter portion as at 119 to engage theupper surface of the base 72 of the valve device, however it is possiblethat this may also cause cocking of the valve device and/or element, andso it is preferred that the keys have at least three of such portions toengage the valve device. Alternatively, if the keys are straight, thekeys could merely extend through the slots 78 and engage the sleeve ofthe latch device 68 to unlock the latch device from the standpipe, whilethe base 108 of the end cap 96 could engage other structure, such assupports 74 on the valve device 64, to cause the valve device to movedownwardly.

It should also be apparent that there are many combinations of keys,slots and tabs that will perform the results of the present invention.It is merely necessary that the keys each have some configuration thatfits between the slots to engage the latch device 68 and the valvedevice 64.

The sealing lip 112 around the base 108 of the end cap seals to thesleeve 70 of the valve device before the opening 49 is uncovered,thereby preventing unfiltered fuel and contaminants from enteringopening 49 along the exterior of valve sleeve 70. Likewise, O-ring 63provides a fluid-tight seal between standpipe 50 and sleeve 70 duringthe sliding movement of the sleeve along the standpipe to preventunfiltered fuel and contaminants from reaching opening 49 along theinterior of valve sleeve 70.

A groove 128 can be provided in the exterior surface of standpipe 50 toreceive the distal ends 82 of fingers 80 when the valve device is in itsopen position. Groove 128 can have an upper chamfered or tapered edge tofacilitate the movement of the distal ends 82 of fingers 80 into and outof the groove. Since the valve device is normally in an open position,this prevents the fingers from tang a set over time, and assures thatthe fingers will properly engage the locking groove 62 when the valvedevice is moved to its closed position. The downward movement of theelement can be limited by an annular shoulder 129 (FIG. 1) on the upperend of standpipe 50 which engages the upper end cap 94 to prevent theelement from pushing the valve element too far down along the standpipe.

As indicated above, the dimensions, number and location of the tabs andslots in the latch device, and the number and location of the keys onthe end cap, determine the correct fit of the filter element in thehousing. The dimensions, number and location of the keys, tabs and slotscan be chosen such that only particular filter elements are onlyinsertable in certain housings. This allows control over the type ofelement useable with a housing and prevents the filter from being usedwithout a filter element.

When it is desired to remove the filter element and replace the filterelement with a fresh element, the lid 24 of the housing is removed, andthe element is simply pulled out of the upper end of the housing. As theelement is removed, the spring 90 assists in moving the elementupwardly, as well as moving the latch device and valve device upwardlysuch that the valve device again closes the opening 49. The spring 90also provides a bending moment on the latch device to force the fingersback into groove 62 to lock the latch device along the standpipe. Theopening 49 is closed by valve sleeve 70 before the annular base 108 ofthe end cap unseals from the valve sleeve, which prevents unclean fueland contaminants from entering the opening. The close contact betweensleeve 70 and standpipe 50 also provides point contact to prevent fluidleakage into opening 49. A shoulder 120 on standpipe 50 limits theupward movement of the valve sleeve.

According to a second embodiment of the present invention, asillustrated in FIGS. 12-16, the fuel filter, indicated generally at 130,can include a pair of mateable housing portions 132, 133, which definean interior cavity 134. The housing portions 132, 133 ate threadablyconnected, and an O-seal 135 can be provided between the housingportions to ensure a fluid-tight seal. An inlet 136 and an outlet 137are provided in the upper housing portion 132, and the upper housingportion includes an opening 138 for receipt of a pump assembly. Lowerhousing portion 133 serves as a collection bowl, and includes a drain139. A water sensor (not shown) can also be provided in the lowerhousing portion, as in the first embodiment. and tabs that will performthe results of the present invention. It is merely necessary that thekeys each have some configuration that fits between the slots to engagethe latch device 68 and the valve device 64.

The sealing lip 112 around the base 108 of the end cap seals to thesleeve 70 of the valve device before the opening 49 is uncovered,thereby preventing unfiltered fuel and contaminants from enteringopening 49 along the exterior of valve sleeve 70. Likewise, O-ring 63provides a fluid-tight seal between standpipe 50 and sleeve 70 duringthe sliding movement of the sleeve along the standpipe to preventunfiltered fuel and contaminants from reaching opening 49 along theinterior of valve sleeve 70.

A groove 128 can be provided in the exterior surface of standpipe 50 toreceive the distal ends 82 of fingers 80 when the valve device is in itsopen position. Groove 128 can have an upper chamfered or tapered edge tofacilitate the movement of the distal ends 82 of fingers 80 into and outof the groove. Since the valve device is normally in an open position,this prevents the fingers from taking a set over time, and assures thatthe fingers will properly engage the locking groove 62 when the valvedevice is moved to its closed position. The downward movement of theelement can be limited by an annular shoulder 129 (FIG. 1) on the upperend of standpipe 50 which engages the upper end cap 94 to prevent theelement from pushing the valve element too far down along the standpipe.

As indicated above, the dimensions, number and location of the tabs andslots in the latch device, and the number and location of the keys onthe end cap, determine the correct fit of the filter element in thehousing. The dimensions, and exiting the filter. These components areconventional in nature and will not be described herein for sake ofbrevity. The components are controllable through an exterior connection(not shown). In any case, fuel through inlet 136 passes around heater164 and into filter element cavity 134. The fuel then passes radiallyinward through the filter element 142 and into the central cavity 141 ofthe element. Particulates and contaminants collect on the exteriorsurface of the filter element and fall down into the lower housingportion, and can be periodically removed through drain 139. The pumpdraws the fuel upwardly through the housing, where the fuel is thendirected outwardly through the pressure regulator 161 to outlet 137.

When the filter element needs to be replaced, the lower housing portion133 is removed, and the filter element can then be accessed, removedfrom the lower housing portion, and replaced with a fresh filterelement. Similarly, when it is necessary to access the pump 150 forinspection and/or repair, cover 152 can be removed from the upperhousing portion and the pump pulled out of the cavity 134.

A valve structure, indicated generally at 166, surrounds the inlet pipefrom the pump assembly, and controls the flow of fuel through opening160. An outwardly-facing locking groove 167 is provided proximate to,and above opening 160. A second groove above opening 160 carries anO-ring 168. A larger groove 169 is provided toward the lower end of theinlet pipe 158 (between the opening 160 and the end of the pipe), whichcarries a larger O-ring 171.

The valve structure includes the valve device 64 (FIG. 8) and latchdevice 68 (FIG. 9) as described above with respect to the firstembodiment. The sleeve 70 of the valve device is dimensioned to bereceived closely around the inlet pipe 158 of the pump assembly, whilethe fingers 80 on the latch device closely surround the inlet pipe, andare biased somewhat inwardly so that they engage groove 167. The latchhousing portion 133 serves as a collection bowl, and includes a drain139. A water sensor (not shown) can also be provided in the lowerhousing portion, as in the first embodiment.

A filter element 140 is mounted within the housing portions andcomprises a ring-shaped media circumscribing a central cavity 141.Filter element 140, similar to filter element 92 in the firstembodiment, can be any filter media appropriate for the particularapplication, and includes an upper or first annular end cap 142 and alower or second annular end cap 143. The end caps 142, 143 are bonded tothe media in an appropriate manner. The filter element 140 is supportedon a series of flanges or ribs 144 integral with the lower housingportion.

A pump assembly, indicated generally at 148, is also mounted between thehousing portions, and includes an electric pump 150 with integrateddrive motor, and an upper cap or cover 152 having an electricalconnection 154 for the motor. Pump 150 can be any conventional type ofpump appropriate for the particular application. One such pump isavailable from AIRTEX PRODUCTS of Fairfield, Ill., with a flow rate of110 Liters/Minute at 60 psi. Cover 152 is removeably attached to pump150 with a series of spring fingers 156. An O-ring 157 is providedbetween the pump 150 and the upper housing portion 132 to provide afluid-tight seal. A cylindrical inlet or return pipe 158 with a centralflow passage 159 extends downwardly from the pump, and has an opening160 along the length of the pump near the inlet lower end to provide apassage for fuel to the pump.

The pump assembly 148 is received through opening 138 in upper housingportion 132, and is received in the cavity 141 of the filter element.Cover 152 is threadably and removeably attached to upper housing portion132. An O-ring 155 can be provided between the cover 152 and upperhousing portion 132 to provide a fluid-tight seal.

The filter 130 can include additional features, such as a pressureregulator 161, thermal valve 162 and heater 164 to control the flow andquality of the fuel entering and exiting the filter. These componentsare conventional in nature and will not be described herein for sake ofbrevity. The components are controllable through an exterior connection(not shown). In any case, fuel through inlet 136 passes around heater164 and into filter element cavity 134. The fuel then passes radiallyinward through the filter element 142 and into the central cavity 141 ofthe element. Particulates and contaminants collect on the exteriorsurface of the filter element and fall down into the lower housingportion, and can be periodically removed through drain 139. The pumpdraws the fuel upwardly through the housing, where the fuel is thendirected outwardly through the pressure regulator 161 to outlet 137.

When the filter element needs to be replaced, the lower housing portion133 is removed, and the filter element can then be accessed, removedfrom the lower housing portion, and replaced with a fresh filterelement. Similarly, when it is necessary to access the pump 150 forinspection and/or repair, cover 152 can be removed from the upperhousing portion and the pump pulled out of the cavity 134.

A valve structure, indicated generally at 166, surrounds the inlet pipefrom the pump assembly, and controls the flow of fuel through opening160. An portion as at 199. Again, each key can also be simply straight,and extend radially inward from the cylindrical portion 181 and axiallyoutward from the base 183 the same amount over the length and width ofthe keys. The lower end cap, including the annular portion 176 and valveactuating portion 177 (with keys 194), is preferably formed unitarily inone piece (e.g., molded from plastic).

The keys 194 of the lower end cap 143 of the filter element, and thetabs 76 and slots 78 on the latch device 64 are arranged such that whenthe filter element is inserted into the housing, at least a portion ofthe keys can fit through the slots 78. The axially longer and radiallythinner portions 198 of the keys fit through the slots 78 in the latchdevice and engage the engagement surface 86 of the sleeve 84 on thevalve device. Similar to the first embodiment, as the element isinserted upwardly into the housing the keys press against the sleeve 84,and cause the latch device to bend and pull the fingers 80 radiallyoutward from the inlet pipe. As the fingers are pulled outward, thedistal ends 82 of the fingers are pulled outward from locking groove167, thus releasing the latch device and allowing the latch device toslide axially upward along the inlet pipe.

Simultaneously with the fingers 80 being released, the radially widerand axially shorter portions 199 of the keys engage the lower surface ofthe base 72 of the valve device to also push the valve device axiallyupward along the inlet pipe, thus uncovering the opening 160. Fuel canthereby flow through opening 160 and then to outlet port 137. The keys194 provide flow paths for the fuel to flow from the radially-innersurface of element to the opening 160 in the inlet pipe. A groove 200(FIG. 14) can be provided upwardly of the locking groove 167 to receivethe distal ends of the fingers when the valve device is in its openposition, such that the fingers do not take set over time. Groove 200can have a chamfer or taper on its downward edge to facilitate themovement of the fingers out of the groove into its closed position.

As in the first embodiment, the dimensions, number and location of thetabs and slots in the latch device, and the dimensions, number andlocation of the keys 194 on the end cap, determine the correct fit ofthe filter element in the housing. The dimensions, number and locationof the keys, tabs and slots, can be chosen such that particular filterelements are only insertable in certain housings. This allows controlover the type of element useable with a housing.

When it is desired to remove the filter element and replace the filterelement with a fresh element, the lower housing portion 133 is removed,and the element is simply pulled out from the lower end of the housing.As the element is removed, the spring 171 urges the latch device andvalve device downwardly in the housing, such that the distal ends 82 offingers 80 eventually engage groove 167, and lock the latch device alongthe inlet pipe. The valve device 64 is also moved axially downward intoblocking relation with opening 160 along pipe 158. It is noted that thevalve structure will likewise move to a closed position when the pumpassembly is removed from the housing (but when the element is notchanged).

The keyed portion of the lower end cap 96 of FIG. 6 can alternatively beprovided as a separate device, as indicated generally at 210 in FIGS. 17and 18. The key device 210 includes an annular base 212 dimensioned tofit within the cylindrical portion 104 of the lower end cap and againstbase 110, and a plurality of thin, flat keys as at 216 projectingaxially away from the annular base 212 and radially-inward toward thecentral axis of the filter element.

Keys 216 are similar to keys 116, and comprise thin and flat strips,equally-spaced in a spoke-like arrangement. Each key has one edgeattached directly to the cylindrical base 212. One free edge of each keyextends outward, away from the base 212, while another free edge extendsradially inward toward the central axis of the filter element.

As with keys 116, each key can have a “step”, that is, an axially longerand radially thinner portion as at 218, and an axially shorter andradially wider portion as at 219. Again, the number, location anddimension of the keys can vary depending upon the particularapplication.

An O-ring seal 222 is provided in a groove facing axially-outward fromthe upper flat surface of base 212, and provides a fluid-tight sealagainst annular base 108 of the lower end cap. A second O-ring seal 224is provided in a groove facing radially inward from the annular base toseal against the valve sleeve.

The remainder of the lower end cap 96 is the same as described above,and includes annular portion 100 fixed to the lower end of the media 92,and cylindrical portion 104 bounding the central opening 101 andextending axially inward into the central cavity 93 to a distal innerend. Annular base 108 extends radially inward from the distal inner endof the cylindrical portion, to define central opening 110. Since O-ringseals 222 and 224 provide a seal between the valve sleeve and the lowerend cap, the flexible lip 112 (FIG. 6) as described above is notnecessary, although the lip 112 can be used alternatively to O-ringseals 222, 224, if necessary or desirable.

The key device 210 is also preferably formed unitarily from anappropriate material, such as an inexpensive plastic. Keys 216 arerelatively simple to manufacture integral with the valve actuatingportion, such as by using common molding techniques.

When the filter element with key device 210 is inserted into the housing22, at least a portion of the keys can fit through the slots 78 in thevalve device, in the same manner as described above with respect to keys116. The axially longer and radially thinner portions 219 of the keys216 fit through the slots in the latch device and engage the annularengagement surface 86 of the sleeve on the underlying valve device. Asthe element is inserted into the housing, the keys press down againstthe sleeve 84, and cause the latch device to bend outwardly and pull thefingers 80 radially outward from the standpipe. As the fingers arepulled outward, the distal ends 82 of the fingers are pulled outwardfrom groove 62, thus releasing the latch device and allowing the latchdevice to slide axially downward along the standpipe.

Simultaneously with the fingers being released by the engagement of thekeys against the sleeve, the radially wider and axially shorter portions218 of the keys engage the upper surface of the annular base 72 of thevalve device and push the valve device axially downward along thestandpipe, in the same manner as described above with respect to FIG. 6.

The keyed portion of the lower end cap 143 of the filter element of FIG.16 can similarly be provided as a separate device, as illustratedgenerally at 230 in FIGS. 19 and 20. The key device 230 has a similar,one-piece structure as the key device 210 of FIG. 18, with an annularbase 235 dimensioned to fit within the cylindrical portion 180 of thelower end cap and against base 183, and a plurality of thin, flat keysas at 236 projecting axially away from the annular base 235 and radiallyinward toward the central axis of the filter element. The keys 236 canhave axially longer and radially thinner portions as at 240, and axiallyshorter and radially wider portions as at 242. The only significantdifference between key device 230 of FIG. 19 and key device 210 of FIG.18 is that key device 230 does not need additional O-0-ring seals toseparate the dirty side of the element from the clean side, as the lowerend cap is closed by cylindrical portion 181 and end wall 182.

The remainder of the lower end cap 143 is preferably the same asdescribed above with respect to FIG. 16.

As described above with respect to FIG. 16, the keys 194 of the keydevice, and the tabs 76 and slots 78 on the latch device 64 are arrangedsuch that when the filter element is inserted into the housing, at leasta portion of the keys can fit through the slots 78. The axially longerand radially thinner portions 240 of the keys fit through the slots 78in the latch device and engage the engagement surface 86 of the sleeve84 on the valve device. Similar to the second embodiment, as the elementis inserted upwardly into the housing, the keys press against the sleeve84, and cause the latch device to bend and pull the fingers 80 radiallyoutward from the inlet pipe. As the fingers are pulled outward, thedistal ends 82 of the fingers are pulled outward from locking groove167, thus releasing the latch device and allowing the latch device toslide axially upward along the inlet pipe.

Simultaneously with the fingers 80 being released, the radially widerand axially shorter portions 242 of the keys engage the lower surface ofthe base 72 of the valve device to also push the valve device axiallyupward along the inlet pipe, thus uncovering the opening 160.

As described above, the dimensions, number and location of the tabs andslots in the latch device, and the dimensions, number and location ofthe keys 236 on the key device, determine the correct fit of the filterelement in the housing. The dimensions, number and location of the keys,tabs and slots, can be chosen such that particular filter elements areonly insertable in certain housings.

Thus, as described above, the fuel filter of the present inventionthereby prevents an improper filter clement from being used in thefilter housing, and prevents operation of the filter without a filterelement. The valve structure is external to the central pipe, which isrelatively cost-effective to manufacture and assemble. In addition, theopening to the fuel passage in the pipe is located toward the bottom endof the housing, typically below the level of fuel, to prevent air fromentering the system.

What is claimed is:
 1. A filter element having a ring of filter mediadefining a central cavity and circumscribing a central axis, said ringof filter media having a first end and a second end; first and secondend caps fixed to said first and second ends, respectively, of saidfilter media, the second end cap having an annular end cap portionsealingly bonded to the second end of said filter media, wherein thesecond end cap has a valve-actuating portion, including an axiallyextending cylindrical portion connected to the annular end cap portionand circumscribing the inner diameter of said annular end cap portionand an annular base connected to the cylindrical portion and extendingradially inward from said cylindrical portion to define a first centralopening which can receive a pipe, the base having a surface facingoutwardly toward the second end, and a plurality of keys supported byand extending away from said valve-actuating portion in an axiallyoutward direction from said base toward said annular end cap portion ofthe second end cap each of said keys having a free engaging portionpositioned radially inward relative to an inner surface of saidcylindrical portion and axially spaced away from said annular base. 2.The filter element as in claim 1, wherein each of said keys includes astep including a first edge portion terminating axially a first distancefrom said annular base and radially inward a first distance from saidcylindrical portion, and a second edge portion terminating axially asecond distance from said annular base and radially inward a seconddistance from said cylindrical portion.
 3. The filter element as inclaim 1, wherein said keys are each thin and flat strips connected tothe valve actuating portion.
 4. The filter element as in claim 1,wherein each of said keys is connected to both the cylindrical portionand said annular base, and the keys extend radially inward from saidcylindrical portion to terminate radially outward from the first centralopening, and extend axially away from said annular base.
 5. The filterelement as in claim 1, wherein said annular end cap portion defines asecond central opening, co-axial with and radially larger than saidfirst opening, and said keys extend radially-inward of the secondcentral opening.
 6. The filter element as in claim 1, wherein saidannular end cap portion, cylindrical portion, base and said keys areunitary, in one piece.
 7. The filter element as in claim 1, furtherincluding a key device for defining said keys, said key device beingsupported against said annular base as a separate component from thecylindrical portion, and is sealingly attached thereto.
 8. The filterelement as in claim 7, wherein an annular resilient seal is disposedbetween the key device and the annular base.
 9. A filter elementcomprising: a ring of filter media defining a central cavity andcircumscribing a central axis, said ring of filter media having a firstend and a second end; first and second end caps fixed to said first andsecond ends, respectively, of said filter media, the second end caphaving an annular end cap portion sealingly bonded to the second end ofsaid filter media and a valve-actuating portion, the valve-actuatingportion including: i) a cylindrical portion connected at one end to andcircumscribing the inner diameter of said annular end cap portion andextending inward into the central cavity from the second end cap towardthe first end cap and terminating prior to the first end cap; ii) anannular base connected to a distal inner end of the cylindrical portionand extending radially inward from said cylindrical portion to define afirst central opening which can receive a pipe, the base having asurface facing outwardly toward the second end; and iii) a plurality ofdiscrete keys supported at one end by the surface of the base andprojecting axially outward from the surface of said annular base towardthe annular end cap portion of said second end cap and having a freeengaging end radially inward of an inner surface of said cylindricalportion and axially spaced outwardly from said annular base.
 10. Thefilter element as in claim 9, wherein said first central opening isinternal to the central cavity.
 11. The filter element as in claim 9,wherein said free engaging end of each key is an edge.
 12. The filterelement as in claim 11, wherein the edges of the keys face the annularend cap.
 13. The filter element as in claim 9, wherein the free engagingends of the keys are internal to the central cavity and face toward theannular end cap.
 14. The filter element as in claim 9, wherein theannular base includes a seal inwardly bounding the first central openingfor sealing against a pipe.
 15. The filter element as in claim 9,wherein the keys are fixed to the annular base.
 16. The filter elementas in claim 15, wherein the keys are unitary with the base.
 17. Thefilter element as in claim 9, wherein the keys have a width projectingradially inward from the cylindrical portion to an inner edge inbounding relation to the first central opening.
 18. The filter elementas in claim 9, wherein the keys are fixed to the cylindrical portion.19. The filter element as in claim 9, wherein the cylindrical portion isunitary with the annular end cap portion.
 20. The filter element as inclaim 9, wherein said keys are axially elongated.
 21. A filter elementcomprising: a ring of filter media defining a central cavity andcircumscribing a central axis, said ring of filter media having a firstend and a second end; first and second end caps fixed to said first andsecond ends, respectively, of said filter media, the second end caphaving an annular end cap portion sealingly bonded to the second end ofsaid filter media and a valve-actuating portion, the valve-actuatingportion including i) a cylindrical portion connected at one end to andcircumscribing the inner diameter of said annular end cap portion andextending inward into the central cavity from the second end cap towardthe first end cap and terminating prior to the first end cap; ii) anannular base connected to a distal inner end of the cylindrical portionand extending radially inward from said cylindrical portion to define afirst central opening which can receive a pipe, the base having asurface facing outwardly toward the second end, and a seal inwardlybounding the first central opening; and iii) a plurality of discretekeys supported by the surface of the base of the cylindrical portion andprojecting radially inward to an inner edge in outwardly boundingrelation to the first central opening, the keys each having a freeengaging end facing the annular end cap portion of the second end cap,radially inward of an inner surface of said cylindrical portion andaxially spaced outwardly from said annular base.
 22. The filter elementas in claim 21, wherein said first central opening is internal to thecentral cavity.
 23. The filter element as in claim 21, wherein said freeengaging end of each key is an edge.
 24. The filter element as in claim21, wherein the free engaging ends of the keys are internal to thecentral cavity and face toward the annular end cap portion.
 25. Thefilter element as in claim 21, wherein the keys are fixed to the annularbase.
 26. The filter element as in claim 21, wherein the keys areunitary with the cylindrical portion.
 27. The filter element as in claim21, wherein the cylindrical portion is unitary with the annular end capportion.
 28. The filter element as in claim 21, wherein said keys areaxially elongated.
 29. The filter element as in claim 21, wherein saidfirst end cap is annular and imperforate.
 30. The filter element as inclaim 21, wherein the cylindrical portion and annular base areimperforate.